release(v1.7.5-alpha): OTA end-to-end test bump

Trivial version-only bump. No code changes; binary differs only in its
embedded CARGO_PKG_VERSION string. Frontend tarball is byte-identical
to v1.7.4-alpha's (same sha), copied under the new filename to satisfy
the manifest component naming.

This exists so the fleet nodes (.116/.198/.253), all now running
v1.7.4-alpha with the fixed apply_update tar flow, can exercise the
full OTA pipeline from the UI: Check → Download (30-min timeout) →
Install (sudo install binary + sudo tar to web-ui.new + atomic swap) →
auto-restart (systemctl --no-block) → sidebar updates → state sync.

Artefacts:
  archipelago                                      7422a695…a1a2a6  40362432
  archipelago-frontend-1.7.5-alpha.tar.gz          4fb79664…0172e9  76984615 (reused)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

core/Cargo.lock

@@ -80,7 +80,7 @@ checksum = "a23eb6b1614318a8071c9b2521f36b424b2c83db5eb3a0fead4a6c0809af6e61"
 
 [[package]]
 name = "archipelago"
-version = "1.7.4-alpha"
+version = "1.7.5-alpha"
 dependencies = [
  "anyhow",
  "archipelago-container",

core/archipelago/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "archipelago"
-version = "1.7.4-alpha"
+version = "1.7.5-alpha"
 edition = "2021"
 description = "Archipelago Bitcoin Node OS - Native backend"
 authors = ["Archipelago Team"]